The body needs fat for
a. strengthening bones
b. building muscles
c. maintaining weight
d. transport of vitamins

The body needs fat for d. transport of vitamins.

But not only does it need fat for transport of vitamins through the bloodstream, but also for their storage, when not used. Only small amounts of “fat-soluble” vitamins A, D, E and K are needed to keep the body in good health, so the excess is stored in the liver and in fatty tissues.

Fat has also several other applications in a body, including proper functioning of the nervous system (fats are constituent in myelin, which wraps around axons in neurons and enables the transmission of electrical impulses in brains), provision of stored energy, as well as formation and development of cells and steroid hormones, which regulate many body processes.

Wikipedia aswell can be used to solve the following questions